package com.jiangruan.javaApiProject.address;


import com.jiangruan.javaApiProject.utils.Base58;
import com.jiangruan.javaApiProject.utils.Hash;

import java.security.*;
import java.security.interfaces.ECPublicKey;
import java.security.spec.ECGenParameterSpec;
import java.security.spec.ECPoint;
import java.util.Arrays;

/**
 * @Creator Date 2021/12/23 9:03
 * @desc:
 * @Description
 */
public class BitCoinAddres {
    //该方法用于生成密钥对，返回密钥信息
    public KeyPair Generatekey(){
        try {
            KeyPairGenerator generator = KeyPairGenerator.getInstance("EC");

            ECGenParameterSpec spec = new ECGenParameterSpec("secp256k1");
            try {
                generator.initialize(spec);
                //生成密钥
                return generator.genKeyPair();
            } catch (InvalidAlgorithmParameterException e) {
                e.printStackTrace();
            }

        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        }
        return null;
    }
    //该方法用于推导得到原始格式地址，并将生成的地址返回
    public  String newAddress(KeyPair keyPair){
       ECPublicKey publicKey  =(ECPublicKey) keyPair.getPublic();

        byte[] pubkey = toUnCompressedPubkey(publicKey);

        byte[] sha256 = Hash.SHA256(pubkey);
        byte[] pubhash = Hash.RipeMD160(sha256);

        //对公钥hash前面添加版本号
        byte[] version = new byte[1];
        version[0] = 0x00;

        byte[] ver_pubhash = new byte[version.length+pubhash.length];
        System.arraycopy(version,0,ver_pubhash,0,version.length);
        System.arraycopy(pubhash,0,ver_pubhash,version.length,pubhash.length);

        //进行双重256，取前4个字节
        byte[] hash1 = Hash.SHA256(ver_pubhash);
        byte[] hash2 = Hash.SHA256(hash1);

        byte[] check = new byte[4];
        System.arraycopy(hash2,0,check,0,check.length);
        //ver_pubhash_check
        byte[] ver_pubhash_check = new byte[ver_pubhash.length+check.length];
        System.arraycopy(ver_pubhash,0,ver_pubhash_check,0,ver_pubhash.length);
        System.arraycopy(check,0,ver_pubhash_check,ver_pubhash.length,check.length);
        //对ver_pubhash_check进行base58编码
        return Base58.encode(ver_pubhash_check);



    }
    //该方法用于返回比特币是否符合规范   address要校验的地址
    public boolean validateAddress(String address){
        if ("".equals(address) || address == null) {
            return false;
        }
        byte[] ver_pubhash_check = Base58.decode(address);
        if (ver_pubhash_check.length<4){
            return false;
        }

        byte [] check = new  byte[4];
        System.arraycopy(ver_pubhash_check,ver_pubhash_check.length-4,check,0,check.length);
        byte [] ver_pubhash = new byte[ver_pubhash_check.length-4];
        System.arraycopy(ver_pubhash_check,0,ver_pubhash,0,ver_pubhash.length);

        byte[] hash1 = Hash.SHA256(ver_pubhash);
        byte[] hash2 = Hash.SHA256(hash1);

        byte[] check_sum=new byte[4];
        System.arraycopy(hash2,0,check_sum,0,check_sum.length);
        return Arrays.equals(check,check_sum);

    }
    //生成未压缩的公钥，并返回
    public byte[] toUnCompressedPubkey(ECPublicKey publicKey){
        ECPoint point = publicKey.getW();
        byte[] xBytes = point.getAffineX().toByteArray();
        byte[] yBytes = point.getAffineY().toByteArray();


        byte[] pubKey = new byte[1+2*32];
        pubKey[0] = 04;
        if (xBytes.length ==32){
            System.arraycopy(xBytes,0,pubKey,1,xBytes.length);
        }else if (xBytes.length>32){
            System.arraycopy(xBytes,1,pubKey,1,32);
        }
        if (yBytes.length==32){
            System.arraycopy(yBytes,0,pubKey,33,yBytes.length);
        }else if (yBytes.length>32){
            System.arraycopy(yBytes,1,pubKey,33,32);
        }
        return pubKey;
    }
//public static void main(String[] args){
//        BitCoinAddres test = new BitCoinAddres();
//        KeyPair keyPair = test.generatekey();
//        String str = test.newAddress(keyPair);
//    System.out.println(str);
//
//}
    public static void run(){
        BitCoinAddres bitCoinAddres = new BitCoinAddres();


    }

}
